Aortic atheroma as a source of stroke - assessment of embolization risk using 3D CMR in stroke patients and controls
Thomas Wehrum1,2, Iulius Dragonu3,4,5, Christoph Strecker3,4
1Department of Neurology, Medical Center - University of Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany. thomas.wehrum@uniklinik-freiburg.de.
Insights
Thicker, vulnerable plaques in the thoracic aorta are linked to cryptogenic stroke. Advanced cardiac MRI (CMR) identified these plaques and potential stroke pathways, highlighting a key cause of stroke.
Area of Science:
- Cardiovascular Imaging
- Neurology
- Radiology
Background:
- Cryptogenic stroke, a stroke of unknown origin, affects a significant patient population.
- Identifying the source of stroke is crucial for effective prevention and treatment strategies.
Purpose of the Study:
- To identify vulnerable plaques in the thoracic aorta using 3D multi-contrast cardiac MRI (CMR).
- To estimate the risk of cerebral embolization from these plaques using 4D flow CMR in cryptogenic stroke patients and controls.
Main Methods:
- A novel 3D multi-contrast (T1w, T2w, PDw) CMR protocol at 3 Tesla was used for plaque detection and characterization in the thoracic aorta.
- 4D flow CMR was employed to map potential embolization pathways.
- Plaque morphology was classified using the modified American-Heart-Association (AHA) classification.
Main Results:
- Plaques ≥4 mm thick were significantly more frequent in cryptogenic stroke patients (55.0%) compared to controls (16.7%).
- Potentially vulnerable AHA type VI plaques (≥4 mm) were found in 17.5% of stroke patients versus 3.3% of controls.
- Six stroke patients with vulnerable plaques had direct embolization pathways to their stroke territory.
Conclusions:
- Plaques ≥4 mm thick and vulnerable plaques in the aortic arch and descending aorta are significant causes of cryptogenic stroke.
- Advanced CMR techniques are effective in identifying these high-risk plaques and their associated embolic potential.
Background:
It was our purpose to identify vulnerable plaques in the thoracic aorta using 3D multi-contrast CMR and estimate the risk of cerebral embolization using 4D flow CMR in cryptogenic stroke patients and controls.
Methods:
One hundred patients (40 with cryptogenic stroke, 60 ophthalmologic controls matched for age, sex and presence of hypertension) underwent a novel 3D multi-contrast (T1w, T2w, PDw) CMR protocol at 3 Tesla for plaque detection and characterization within the thoracic aorta, which was combined with 4D flow CMR for mapping potential embolization pathways. Plaque morphology was assessed in consensus reading by two investigators and classified according to the modified American-Heart-Association (AHA) classification of atherosclerotic plaques.
Results:
In the thoracic aorta, plaques <4 mm thickness were found in a similar number of stroke patients and controls [23 (57.5%) versus 33 (55.0%); p = 0.81]. However, plaques ≥4 mm were more frequent in stroke patients [22 (55.0%) versus 10 (16.7%); p < 0.001]. Of those patients with plaques ≥4 mm, seven (17.5%) stroke patients and two (3.3%) controls (p < 0.001) had potentially vulnerable AHA type VI plaques. Six stroke patients with vulnerable AHA type VI plaques ≥4 mm had potential embolization pathways connecting the plaque, located in the aortic arch (n = 3) and proximal descending aorta (n = 3), with the individual territory of stroke, which made them the most likely source of stroke in those patients.
Conclusions:
Our findings underline the significance of ≥4 mm thick and vulnerable plaques in the aortic arch and descending aorta as a relevant etiology of stroke.
Clinical Trial Registration:
Unique identifier: DRKS00006234 ; date of registration: 11/06/2014.
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